James Montgomery, Associate Editor, RenewableEnergyWorld.com
February 05, 2014 | 3 Comments
New Hampshire, USA -- A busy couple of days for energy storage on both sides of the meter: WattJoule says it's figuring out how to finally solve the puzzle for reliable cost-competitive vanadium redox flow batteries, Primus Power lands more funding for its own flow batteries, and Green Charge Networks tallies up new customer installations, including many tied to solar energy systems.
WattJoule: Solving the Vanadium Redox Flow Puzzle
WattJoule says it's on the way to solving the puzzle of affordable flow battery technology, thanks to the recent pairing of two technology tracks.
Back in December WattJoule somewhat decloaked with word that it was licensing technology from the Oak Ridge National Labs (ORNL) and U. of Tennessee. A few days ago the company followed up with another licensing deal, this time with Battelle for IP developed at the Pacific Northwest Labs (PNNL). Both are key to pushing the company's vanadium redox flow battery technology, explained Greg Cipriano, WattJoule founder and VP of business development. The ORNL tech improves the flow battery's power performance, which the company has applied to altering some of the materials and stack componentry and overall design. The PNNL technology addresses the energy side of the equation, helping more than double the energy density in the company's electrolyte and widening the temperature range (now up to 60°C and down below 10°C), both of which help improve the system's scalability and associated costs.
Put together, the two technologies give a clearer overall picture of how the vanadium redox processes interact, and thus can be most effectively improved -- into a 65 percent cost reduction in just the material content, Cipriano claimed. "The big surprise was how far off how people working on flow batteries were, how flow batteries work and function," he said. "The fundamental understandings here are really a quantum leap." (The combined broader understanding also separates WattJoule from other companies that have licensed the PNNL tech, including UniEnergy, he said.) The company has "80 percent of the solution" to making the battery tech commercializable, with the remaining 20 percent involving other ways to get the overall system costs down. Some of that, he revealed, has been reaching out to nearby U. Mass-Lowell and its stellar polymer (plastics) research, to incorporate "copious" amounts of durable plastic components instead of metal machined parts.
Cipriano claimed the company has essentially finished its first-generation product and is tweaking the system to maximize charging/discharging, on a runway of about 2.5-3 years to market introduction. The next generation will utilize a new electrolyte, which he suggested could use less vanadium or even none at all. Addressing questions about performance and longevity vs. system costs and O&M, he noted that the stack doesn't require exotic equipment and the electrolyte is mostly water-based. And pumps and filters can be designed in redundancy for failure or O&M, without the safety concerns of lithium-ion technology.
He also questioned projections about pricing and matching li-ion technology, claiming that technology is already at scale which removes the best and most obvious cost-reducing factor. Best pricing for li-ion is around $400-500/kwh but at the cell level, he said, suggesting that the overall stack is more like $600-$700/kwh.
Near-term the company is looking for funding. After its founders put in seed capital, Cipriano said they're now actively recruiting investors for a first official round of funding which he said should happen by late spring or early summer. They already have a term sheet with an unidentified strategic investor from the wind development community, he said; ideally they'd want a consortium of investors including the venture capital community, which he characterized as "still a little standoffish" after a few years of downturn but willing to listen.
Vanadium redox is getting special attention as an alternative to lithium-ion battery technology, storing energy in liquid form to repeat charge/decharge cycles many times without damaging any system parts, explained Sam Jaffe, senior research analyst at Navigant Research.
Jaffe's not convinced that lithium-ion battery tech has exhausted its cost-cutting abilities. "I wouldn't make that bet," he said. And system reliability is a key concern with any flow battery: there's a big leap between making a pump work, and proving its reliability with 99.9 percent certainty over 15 years, he said. "Anyone that's going to manage a big set of batteries, if they have a choice between traditional electrochemical cell encased in metal and a flow battery with pumps and fluid moving, they'll choose the solid-state cell," he said. "When you have something that literally sits there, done on the molecular scale, anybody would prefer to make an investment in that."
Next: Funding for Primus Power's Flow Batteries